Peter and I both happen to be reading the book Silent Spring by Rachel Carson, a legendary work that helped launch the environmental movement in the US in the mid-20th century.

In the book, Carson describes the detrimental effects of pesticides on the environment and assails the chemical industry for irresponsibly unloading compounds into the ecosystem without regard for their effects on ecological (and thus human) health.

As she wrote: “Can anyone believe it is possible to lay down such a barrage of poisons on the surface of the earth?”

While much progress has been made since the publication of Silent Spring (including the banning of the pesticide DDT and revolutionary changes in US environmental policy), contemporary society continues to suffer from self-inflicted exposures to metals, solvents, pesticides, and other chemicals in the environment that are known to cause severe neurodevelopmental damage that can impact brain aging.

The barrage of poisoning continues.

One troubling exposure that we have written about in The Myth of Alzheimer’s and on the blog is mercury, a neurotoxin whose deleterious neurological effects have been documented for centuries, and even depicted in classic works of literature such as Alice in Wonderland. In the 1800s, hat-makers used mercury to treat fur and felt, and this occupational exposure caused them to shake, tend towards aggression, and suffer from irrational behavior and mood swings. Lewis Carroll famously captured this phenomena in his depiction of The Mad Hatter.

Research in the past several decades have demonstrated the dangers of mercury poisoning during fetal development and early childhood when exposure can damage the nervous system and cause learning disabilities at doses much lower than those affecting adult brain function. Additionally, there is some evidence that continual exposure may also predispose older persons to increased risk for dementia later in life.

While we have always known that mercury is prevalent in the environment, originating largely in coal-fired power plants where it is spewed into the atmosphere before falling to earth’s surface in precipitation and particulate matter, a study released yesterday by the U.S. Geological survey brought home just how pervasive the neurotoxin is in our national fish supply.

The 7-year study sampled fish from 291 freshwater streams, revealing mercury contamination in every one of the hundreds of fish sampled. More than a quarter of the fish in the sample contained concentrations of mercury exceeding levels set by the Environmental Protection Agency, while more than two-thirds exceeded the EPA-set level of concern for fish-eating mammals.

This essentially means that almost every fish that ends up on our plates will have some degree of mercury in it — a fact that would likely inspire great sadness, even indignation, in Rachel Carson.

Clearly action is needed.

As this article on yahoo.com explains, the Obama administration has said it would begin crafting a new regulations to control mercury emissions from power plants after a federal appeals court threw out plans drafted by the Bush administration and favored by industry that would have allowed power plants to buy and sell pollution credits instead of requiring each plant to install equipment to reduce mercury pollution. Moving towards clean energy is also an essential “federal-level” step in reducing damaging anthropogenic contributions to the environment.

In the meantime, what can we do as individuals? As we recently suggested on Beyond the Myth, given the known benefits of omega-3 fatty acids for neurological health, it seems wise to keep eating fish, but in moderation.

The type of fish we eat is also important. While mercury and other neurotoxins leach into the skins of all sea-dwelling creatures, smaller species tend to bio-accumulate less than larger species. Follow this link to a good visual representation of mercury levels in commonly-eaten fish.

The last suggestion would be to read Silent Spring along with Peter and I and take some time to go out into nature and be humbled by the wonders and realities of the ecological environment that sustains us despite our occasionally unwise behaviors. As Rachel Carson wrote, “Wonder and humility are wholesome emotions, and they do not exist side by side with a lust for destruction.”

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